Steam and air injector



Sept. 25, 1928.

J.- DOHERTY STEAM AND AIR INJECTOR 1 Filed April 24/1923 2 Sheets-Sheet1 Sept. 25, 1928.

J. DOHERTY STEAM AND AIR INJECTOR Filed April 24, 1923 2 Sheets-Sheet 2James 001/52 f).

' 1,685,482 FIGS...

muss mums, n (amass. mammacrim. AND! AIR nma es ATENT or star a i m Ann2. s i s I9-.634..-232- The present invention relates to boiler andfurnace construction, and has particularly to do with means forincreasing the 'combustibility of fuel. H "Reference will be had atvarious tunes to my Patent 1 402,843, issu-ed January 10, 1922,

' and one of the objects of this invention is to provide a modificationof and'improvement upon the construction therein described.

Another of the invention isto rovide in a single furnace an adaptabi itywhereby coals of different types may be burned with e ual efficacy, theinvention providin means or securing complete and regulated combustionof such fuel.

Another object of the invention is to tovide means for introducing airand steam at various joints within the combustion ch an ber and nopassages of a furnace or boiler in order to promote com lete oxidationof the fuel material and fue gases. It is contemplated that such steamand air will be admittedto the fire box and flue passages in regulatedportions, and that the steam' will be injected transversely of the gastravel in the boiler or furnace, and that the air will have a controlledtemperature.

The invention comprises, in part, the manner of introducing and heatingair to be supplied to the combustion chamber, in part, to the manner inwhich steam is introduced therein, and in part, to the. arrangement ofthe air and steam passages and of" the steam supply means withinthe'fnrnace structure.

These objects, and such other objects as will hereinafter appear, areattained by the construction, combination and arrangement of parts nowto be described.

The acmmpanying drawings illustrate the preferred form of the invention,and it will be manifest from thedescription herein that the constructionand arrangement thereof may be varied without departing from theinvention. Y

In the drawings:

Fig. 1 is a perspective view of a typical sectional. water-heatingfurnace with the side wall broken out and the interior parts shown in i'ertical'and oblique sections; Fig. 2 is a transverse sectionadjacentthe front water curtain therein;

- Fig. 3 and Fig. tare details of the steam pipe construction, and nFig. 5 is a plan view of oneof the sections of the air duct formingmembers.

Like reference characters are used todesignate similar parts in thedrawin and in the description the, invention whic follows,

The furnace shown thedrawing is enlly of t s yp a hat i us a in mypatent referred to above, and com rises front a k a r-c n ning sec ion 1and and a p u a ity o in ermed Wa containing sections, 3, 4, 5, 5' and6. all of which sections have the same eneral external configuration andareadapted to be clam d or otherwise secured to one another, ad is usualin sectional boilers, The water spaces of each intermediate section andthose in the front: and back sections 1 and 2 are in communicat on, asis also customary in boiler construction. i i

i In assembled relation, the several sections referred t fi P o id thefire h x and h flue pa f r xpo i the qui it ur ace for the transfer ofheat from the combustion vgases to the water withinthe water s aces.

To increase the surfaces ex osed to the heated gases of combustion aswelyas to augment the water covered surfaces, sections 3 and resubstantially of a T-shane in cross section, tie depending portion, orthe stem of the T, being shorter inthe latter sections. sections 3 and 4form the roof or crown of the fire box which has its greatest vapor caacity immediately adjacent and in front o section 5 which comprises across member or bathe containing a water space and dependingconsiderably below the crown wall'of the'fir Said section marks the rearlimit ofthe upper part of the fire box and providesa water curtainintermediatethe front and rearpor- 'tions thereof.

After combustion gases ass through the I flue spaces in section 6 andetween sald'section and the adjacent sections 3 and 5,

gases are passed forwardly through horizontally directed side flues 7and then rearwardly rough a ho i ontal c nter flu 3 ar ange p a l to fins 7 o the ake-eff an c mney,

which latter are not illustnatedy The flue-.2)!- rangement described isat new and is not essentialto the success of t e invention, about to bedisclosedfoi other fluetarrangements may be employed without decreasingthe'efficacy of the invention.

The bottom of the firebox comprises a per forate up draft grate 9 and isordinarily arranged in parallel relation to the-crown wall and hence issubstantially horizontal. Its rear end terminates withand abuts upon thevertical portion or a bridge'\\"all or banlclO which is upwardlyinclined as it approaches thelowermost and depending section ofsecfaonpr section 5? at the rearofjthe furnace.

' Coal is supplied in the usual manner through a feed door'in the frontsection 1 and air admitted to and beneath the fuel bed upon the grate 9by'an ash pit door also dis- Jposed in'said section 1 and at the bottomthereof, The air admitted through said ash pit door, of course,constitutes the major portion of a'iremployed in obtaining combustionofthe fuel in the fire box. M i I have designated the water curtain ofsectioii;5j by the ordinal 11. The loweredge thereof extendstransversely and horizontally over the rear part of the grate 9 and fuelbed, occupying a level "which issomewhat "'nf earer to the gratethan wascrown wall, and "in this position, as in Patent 1,402,848, it cooperateswith the fuel bed directly below it, to form therewith asomewhatrestricted passa geway or throat through which the fire box opens into.the'fiue space at its rear. Sub- 'stantially the entire volume offire'gases developed in the furnace flows through this pastil sagewaywhich extends across the furnace with practically uniform verticaldimension. As in the patent referred to above, a ductsubstantiallycoextensive with the water curtain V 11 is provided,saidduct being'designated by the ordinal 12, and is substantiallycoincident with the lower edge of said water curtain. Atmospheric air isadmitted to said duct through appropriate damper-controlled inletopeningsflil in the side legs of section 5, as shown in Fig. 2 and suchair is discharged from'and distributed through a plurality of uniformlyspaced and downwardly directed exit orifices 14 opening upon the lowerside of duct 12, and therefore, in the direction of the fuel bed. Suchair flows into and through said duct and its orifices because of thechimney suction which sufhces to produce a vigorous discharge throughthe row of orifices and because the air path through the grate 9' ismoreor less obstructed by the fuel thereon. .The velocity is so great as tocause the air to penetrate .the throat passage above referred toandseemingly to impinge against the subj'acent bed of fuel, creating anextraordinary mixing effect and turbulence in the fire gases at thatpassage which is manifested in practical operation by a'sheet oflividlwhite flame extending directly from the water curtain 11 to andthrough the horizontal hues of "theffurn'ace. 1

,walls.

nient of water sections of less vertical'dimensions, as indicated bytheuse. of sections 4, immediately in front of the Water curtain 11contained in section 5, increases the gas space adjacent said sectionand materially assists in the securing of awhirling of the generated.fuelgases, causing most intimate mixture thereof and of thesupplemental air admitted by duct 12, whereby substantially completecombustion of such gases is obtained.

The general construction of section 5 has not been modified over thatdisclosed in my earlier patent. The upper and front portion of Watercurtain, 11 is completely protected by a vertical tile fire-wall15contiguous to the water curtain 11 at itsfront, and said wall ismaintained 'in position by resting upon the exterior upper surface ofduct 12 and bycontact between a portion of its upper section and theenlarged portion of theside legs of the furnace adjacent thecrown wall.V

combustion chamber through the duct 12, passes between a series of teeth16 formed along the loweredge of the water curtain 11 and providingtherebetween the exit orifices. 14, said teeth. being of substantiallyequal size and all containing Waterfrom the water curtain 11. The duct12 is completed by resting upon teeth 16 two L-shaped members 12 whichmay be described as abutting channel bars l1aving..af1'ib.17 ofincreasing width as the side ofthe section "5 is approached.

The spaces le intermediate the teeth 16 are substantially of the .samewidth as the teeth The atmospheric air as it is admitted to the v Ill)themselves but their otherjdim'ension is 'grad- 1 I uated by rib. 17 sothat while air is delivered .to the fire box in closely adjacent anduniformly spaced jets or blasts, s uch jets are of greater cross sectionas (in one dimension) the center of the fire box is approached. Such anarrangementinsuresadmission of air in equal volume through each orifice1a and tends to prevent localization of the air supply-at theorificesadjacent the section side as it is jetted into the fire box is mainlyclownwardly and slightly forwardly; andaturbu- The direction oftheairgmovement combustion cha'i'nber issuch as to disturb the i vgeneral direction and movement of the-conibustion vapors. The. wall 15,being struc;

amuse turally separate from section 5, is entirely free to expand andretract under thermal changes which occur inthe combustion chamber ofthe furnace without injury to itself and without imparting strain to orupon the metal of the water curtain proper or to the Wallsof section 5.

' It is well established, and equally well evidenced by a number ofpatents which have been granted, that the admission of steam, if it isproperly legulated, to a fire box in order that it may comingle with thecombustion gases, has a salutary eflect upon combustion, rendering itmore complete and increasing the volume of heat units obtained. So faras I have been advised, none of the devices which heretofore have beenpresented, has caused the proper comingling of thesteam with thecombustion gases, and therefore the devices have been failures orpartial successes. It is also a tly demonstrated that the admission tothe box and fines of supplemental air, in regulated quantities, and withproper conditions of ingress, tends to increase the combustibility offuel'n'iaterial, and permits of complete oxidation of the carbon thereofwithin the walls of the furnace, doing away with the loss of heatresultant from partly consumed fuel va ors or gases, and overcomingsmoke nuisances. I will now describe my improved methods of admittingsteam and air, to a furnace whereby to cause proper corningling thereofwith the combustion gases thereof. Such description willalso include themeans Wl'iieh I have employed whereby such air and steam may be admittedat various stages of fuelcomhustion with the combustion gases andcat'ise their complete oxidation and maximum heat'development.

, I have found, from actual practice, that in ccrtain'classes of fuel,air which is admitted through the updraft grate 9 and through duct 12 insection in which is formed the water curtain 11, is insuilicient toprovide complete combustion of the fuel, and the gases generated by suchfuel, and such gases reach the flue spaces rich in uncombined carbon andother combustible products which may be made to ignite and roduceadditional heat, if additional air is admitted at. the proper point inthe combustion space. To overcome this condition, immediately adjacentthe rear section 2 and intermediate said section and section 6 through.which flue spaces are arranged, a section '5, identical with section 5,is pmvided. Air there admitted is adapted to be thrown verticallydownward and slightly forward againstthe inclined top of wall in orderthat it may quickly mix with the onrushing current of heated gasesendeavoring to reach the horizontal titles 7 and 8 above. I It will benoted that gases which ass under'the water curtain 11 willattain a highsontally through duct 12.

"curtain l1 and throu h the restricted throat thereunder. This beingtrue, atmospheric air admitted through section 5* will have considerablevelocity, enough to cause it to impinge and agitate and rapidly cominglewith the heated combustion gases. Such portions of the combustion gasesas have had insanicient intermixture of oxygen to be completely consumedin the fire box and flue space adjacent thereto will take fire adjacentthe rear flue space 6 and in the horizontal upper fines, thus increasingthe heat values tobe' transferred to the water in the spaces about thesefiues. It is, of course, contemplated that the openings into ducts Hand12' will be damper controlled.

To convey a volume of steam to the combastion chamber and flue spaces inorder that the steam may be decomposed into oxygen and hydrogen orotherwiseaid combustion and increase the value of the burning fuel, Iprovide a pipe Which is bent to pass from the to of one of the furnacesections, preferably t iat'of section 5, downwardly and hori- A luralityof vents or openings are arran upon said pipe, coextensive with the duct19, in order that steam may escape therefrom in a finely atomizedcondition. The openings of said cent are preferably in a sin le row anddownwaldly' pointed and may in so disposed as to coincide with the exitorifices 14. A valve (not shown) may be placed at any convenient pointupon said pipe 20. ,Said pipe 20 is'continued out of and be yond duct 12and passes horizontally under the updraft grate 9,, where a plurality ofo nings or vents similar to those described a ve are arranged in the topsurface of the pipe. A second valve (not shown) may be provided uponpipe 20 at any convenient point intermediate its two horizontalsections. In the arrangement thus described, steam is finely divided oratomized before sslng into the combustion chamber. That which isreleased in the duct 12 passes therefrom in intimate mixture with theair admitted through said duct and impinges the burning! combustionvapors 1mm above while moving in a vertical downward direction formingwhat may be aptly termed a curtain of vapor across the restricted throatpassage beneath water curtain 11. The steam so discharged into thecombustion chamber has equal or greater velocity than the air'with whichit is mixed, and immediately comingles with the combustion vapors,creating great turbulence therein, and producing immediately changes r nwhich ase the combustibility o the gas mixture.

I Steam'va 301 dischar ed verticall u )ward bet, behaves in thesamemanner. as thefsteam which is admitted into the duct 12,: It too ismingledwith air. This 'may become part of. the curtain of vaporpreviously; adverted to. The perpendicular. flow ofsteam-vaporfronrabove andfroni below the'fuel bed .differs from the steam flowproduced by other devices, so far as I am informed, in that'none ofthese otherdevices secures proper and intimate admixture of the steamvapor and the combustion gases, and 110% provides means forcreating asteam or vapor curtain through which the combustion gases mustnecessarily pass on their journey to the flue passages.

- In the rearwardly disposedsection 5 I have also provided means for.atomizing steamlvapor, and allowing it to comingle with the air admittedthrough said section, for the .pipe 21 passing into duct 12 in section5* is connected with pipe 20 to receive steam therefrom. If required, avalve may also be placedupon pipe 21 at any convenient point. a a

-An additional supply of steam may be employechwithout admixing suchsteam and air, through the agency of pipe 22, valve controlled butvalvenot shown, which pipe is disposed nnmedlately ZIdJilCeDt to andrear-.

ward of the rearmost of sectionsi-B above the fuel bed. The vents oropenings for the discharge of steam therefrom are, preferablydisposedupon the under s-idethereof in order that the steam dischargedtherefrom will driven downwardly into thefvaporsbeing generated upon thegrate 9 and increasethe whirling movement of said vapors between thevfire bed and crown wall. Each of said pipes, 20, 21 and 22, may beprovided with means whereby to cut oil the flow ofsteam adapted to'be;discharged therefrom,-just as each of sections 5.has a damper for thecon trol of the admission of air thereto.

. A fire is begun in the usual way in my furnace; The portion of thefuel adjacentto section 1 takes fire first. That portion adjacentsection 5 cokes more'rapidly because the gasestherefrom comingle withthe airand the steam admitted from section and pipes 20 and 22. Thegases pass, under the Water curtain lland into the combustion space atthe rear of the boiler where additional steam servation of combustionconditions within the fuel ch amber and of the smoke dlscharged from thechimney. Instead of the yellowishwhite and sooty flame which isordinarily present in most boilers and particularly so with certainkinds, of fuel, there should be fdeveloped,rapidlyan. incandescent flameindicative of,admixture with the fuel gases .of ;a sufficient supply Aof; oxygen". Tests] show greatly increased heat, ,both ,in volume and in.temperature.- lheefiect produced is notunlike that of the Bunsenburner; where air and gas may be mixed in order to',compl etely consumethecarbonparticles within the gas,

doing awaytwith, un consumed particles. producing both ilhuninationandcarbon deposits.

;-The additional portions ofair, together with fireworkstoivardthefront. of the furnace and fully consumesthe-fuel, leaving onlya finely disi ashgw y o s The arrangement ofthe several. sections of theboiler may be Tvaried .atwill, and I do not want to be. limitedto-either the particular constructlon; or. the particular, arrangementherein shown, for the essence of theinvention is not any, particular vand specific construction of theboiler, itself, but is the arrangementof air ductsin .properjpositions'to insure more-complete -.combu stion,andlin the mannerof admittingsteam to theboiler to obtain a properadmixture and comingling of such steam with the combustible elements ofthe fuel gases. ,Ofcourse, with respect to the employment ofsupplemental air, I have provided; the samegeneral means for insuringadmissionof such air, and for obtaining its admissionat a propertemperature, as I provided in prior patent, hereinbefore frequentlyreferred to.

It is quite manifest which is given here that the water curtain andother features of section F could with equal facility be nadea part ofrearvend section 2 without departing from the spirit of invention ormodifying the eificiencyof the device. i t lVhatI claim as new anddesireto secureby Letters Patent oftheUnited States,is: Y 1. An air andsteam injectorfor use furnace or the like, comprising an air ductprovided with air-passages of graduated and increasing sizeas the centerof the furnace is approached whereby an equal volume of air isdistributed from each of said passages and transversely of the directionof flow of combustion vapors in said furnace, anda steam supplyingmember provided with a series of equidistant-1y disposed orificesadapted to discharge equal, volumesof steaminto each of said airpassages. 1

,2. A furnace having. a fire boX, a grate, a water curtain, and. abridge wall adapted to form a transverse restricted passageway into therear, portion of the firebox-and between ntegrated; completely exhaustedfrom the description 7 i in a admitting air to said furnace from theside thereof and for distributing such admitted air thereacross to forma curtain of uniformly mixed steam and air.

3. The combination as defined in claim 2 and in which said means foradmitting air comprises a transverse air passage associated with thewater curtain, the transverse air passage having graduated aperturestherein, and in which said steam admitting member comprises an aperturedpipe positioned in said transverse air passage and designed to dischargesteam into said passage to become mixed with the air therein before thedischarge thereof through the graduated apertures.

4. The combination with a furnace comprising a fire box, and flue, and agrate in said firebox and designed to support material in combustion, ofa bridge wall against which burning material is designed to be banked, awater curtain depending from the roof of said firebox and in advance ofsaid bridge wall forming a restricted passageway across said firebox,means for discharging a mixture of air and steam from a sectionalportion of said water curtain, and means for discharging steam upwardlythrough said grate in a region directly beneath said water curtainwhereby a mixed curtain of steam and air is produced across saidrestricted passageway. v

5. The device described in claim 2, and having means for admitting steambelow said restricted passage.

JAMES DOHERTY.

